Glue them in with Gorilla Glue. When exposed to moisture,it expands as it hardens and will hold the weight tubes tight. No rattle and no weight tube blow back when stumping and hitting hard targets. Place a few drops of GG inside the shaft, either end, and rotate the moisened weight tube as you push it into the shaft. Apply a few drops of additional GG every 3-4″ as you rotate the weight tube into the shaft. Obviously you need to account for the lenght of the BH and nock adaptors when cutting the weight tube before glueup.